The present invention relates to a method for ensuring quality during the scanning and/or copying of images and/or documents. The present invention also relates to an arrangement for carrying out the method according to the invention.
WO-A1-95/12271 describes a method for scanning documents in which the skew and size of the document to be scanned are checked. Depending on the result, the scanning signal is modified in order to compensate for the skew.
U.S. Pat. No. 5,073,953 describes a system for automatic segmentation of a scanned document in order to separate areas with different types of information in the document, for example; text, images, etc. The document is subdivided into a number of partial images that are then classified. In order to increase the speed of the system, the number of classes and/or partial images is chosen to be greater than the number of information types that are to be distinguished.
U.S. Pat. No. 5,159,667 shows an automatic identification method for scanning documents. The method relies on recognizing different global characteristics of different documents and/or forms and compares this information with a database of known document types. The system classifies different parts of the document based on that information.
U.S. Pat. No. 5,510,896 describes a digital copier including an automatic copy quality correction and calibration method. The correction and calibration method is performed using a known test original. The result of the correction and calibration method is to give a basic quality to the digital copier.
Common to the abovedisclosed methods for scanning documents is that they only solve one or a few of the many problems one encounters when scanning and/or copying images and/or documents.
The object of the present invention is to provide a method for ensuring quality during the scanning/copying of images/documents, as well as an arrangement for carrying out the method. The purpose of the invention is to ensure the quality of the entire result of the scanning/copying process. The method for ensuring quality is performed every time a document is being fed in, making use of each separate document, not a known test original. This will improve the quality further.
These objects are achieved by a method that includes a number of is steps, the method starting by the page(s) to be scanned and/or copied being fed in. Thereafter, parameters for outer characteristics concerning skew, double feeding/overlapping, deviating shape and geometric deformation are measured in order to calculate a first quality measure, Q1, which represents outer quality. Thereafter, the first quality measure Q1 is compared with a predetermined quality limit Q+1. If the quality limit has not been reached, that is, if Q1 less than Q+1, then a warning is sent out in order to perform re-feeding. If, however, Q1xe2x89xa7Q+1 then the outer quality is automatically adjusted through geometric transformation in order to improve the first quality measure Q1. The next step is to perform an analysis of the contents of the page with respect to structure and objects in order to calculate a second quality measure, Q2, which represents inner quality. Thereafter, the second quality measure Q2 is compared with a predetermined second quality limit Q+2. If the quality limit has not been reached, that is, if Q2 less than Q+, then a warning is sent out in order to perform re-feeding. If, however, Q2xe2x89xa7Q+2, then image improvement methods are performed on each identified object. An information analysis is then performed on each page, followed by a comparison with pre-defined forms and/or document types in order to calculate a third quality measure, Q3, which represents the information/ context quality. The next step is to compare the third quality measure Q3 with a pre-determined third quality limit Q+3. If the quality limit has not been reached, that is, if Q3 less than Q+3, then a warning indicating document error is sent out. If, however, Q3xe2x89xa7Q+3, then a fourth quality measure, Q, is calculated, which is a weighted combination of the quality measures Q1-Q3. The quality measure Q is compared with a pre-determined fourth quality limit, Q+, which represents an overall quality limit. If Q less than Q+, then a warning is sent out indicating insufficient quality. If, however, Qxe2x89xa7Q+, then pre-processing is performed in order to obtain the correct output format, depending on pre-defined information about the printer/output unit.
The present invention also relates to an arrangement for ensuring quality during the scanning/copying of images/documents, the arrangement including an interface/communications logic unit that is connected to and communicates with an image input arrangement and with an image output arrangement. Additionally, the arrangement includes a control and monitoring unit connected to the interface communications logic unit. An image memory unit for storing image information is connected to the interface/ communications logic unit. The arrangement also includes a device, connected to the control and monitoring unit and to the image memory unit, for measuring outer characteristics concerning skew, double feeding/overlapping, deviating shapes and geometric deformation. These parameters/measures are used by the control and monitoring unit to calculate a first quality measure, Q1, which represents outer quality. Connected to the control and monitoring unit, the image memory unit and the device for measuring outer characteristics, is a device for automatically performing an adjustment in the form of geometric transformation in order to improve the first quality measure Q1. The arrangement also includes an analysis device that is connected to the control and monitoring unit, the image memory unit and the device for automatic adjustment. The analysis device analyzes the contents of the page with respect to structure and objects. This analysis is used by the control and monitoring unit to calculate a second quality measure, Q2, which represents inner quality. Connected to the control and monitoring unit, the image memory unit, and the analysis device, is a device for performing image improvement methods on each identified object. The arrangement also includes a device, connected to the control and monitoring unit, the image memory unit, and the image improvement device, for performing an information analysis of each page. The information analysis is carried out relative to predefined form and document types. The information analysis is used by the control and monitoring unit to calculate a third quality measure, Q3, which represents information and context quality. Connected to the control and monitoring unit, the image memory unit and the information analysis device is a device for performing pre-processing in order to obtain a correct output format depending on predefined information about a printer/output unit connected to the arrangement.
The invention will be defined in greater detail below in connection with the drawings.